Sizing and method of preparing same.



"165. com Posmofls,

COATING OR PLASTIC.

I ED STATES PATENT OFFICE.

ANDREW A. DUNHAM, OF BAINBRIDGE, NEW YORK, ASSIGNOB 'IO CASEIN COMPANY OF AMERICA, A CORPORATION OF NEW JERSEY.

SIZING AND METHOD OF PREPARING SAME.

1V0 Drawing.

Specification of Letters Patent.

Patented Dec. 2, 1913.

To all whom it may concern:

Be it known that I, ANDREW A. DUNHAM, a citizen of the United States, residing at Bainbrid e, in the county of Chenango and State of ew York, have invented or discovered certain new and useful Improvements in Sizings and Methods of Preparing Same, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention or discovery has for its object the production of a starch sizing which may be used in connection with certain cla s for paper-coating purposes so that the coating may be applied in a better manner than has hitherto been possible.

Starch sizin 's are now being largely used E in tlie paper coating industry, and these 5 sizings are made by treatin 20% starch with various chemicals in sue a manner That swhen the starch is dissolved by means of ;water and heat it has a proper consistency -"for mixing wi 1 him clay, ul 9 colors and earth bases in genera arc sizing preparations, w en mixed with certain la s or kaolins have the peculiar property 0 t lckening the same to such an extent that the mixture cannot be satisfactorily used for paper coating purposes. For example, if 18 parts of starch sizin dissolved in four arts of 17131392, hehadhed to 190 artts, of cor a c a w 10 as revious een 'fiixed wltli lOO parts of water, the ni ixture, instead of becoming thin and flowing freely with paper coating brushes, will become thick and spongy to such an extent that it cannot be run on a coating machine without leaving the aper in an uncommercial state, owing to rush marks and want of uniformity of the coating. The same sizing mixed in the same proportion with an En lish kaolin will produce a coating which w1 workout free,-flow well and coat the paper in a fairly satisfactory manner.

The reason for variance in the action 22 the starch sizingsp'n d fie rentmsiof cia 15 not well known. Theories' iiafvebeeifa vanced that in one case the clay may contain more humic acid than in another case, and that tElS variation of humic acid accounts for the difference in the co-action of the clays and sizings. While it is not certain that this explanation is correct it has been discovered that if a small percentage of an alkaline silicate, preferably silicate of sgfla, eitlier m :1 dr or a wet form, E added 0 a modifigd stgr cg sizipg or to the claythe resulting mixture will Work satisfactorily for paper coating purposes. The amount of slllcate of soda, or other alkaline silicate, which will ordinarily be used will be about 4% of the dry starch sizing, but this percentage may require some variation for use with different clays from different localities; so that the invention or discovery is not to be understood as being limited to any prescribed percentage of the alkaline silicate, which may be s1licate of soda, silicate of tash or any F5551 equlvalent alkaline s1licate.

A good example of the proportions of materials suitable for a or coating under this new discovery wou d as follows: To 180 lbs. of dr modified starch sizin add about 7.2 lbs. oi dr alkaline slllcate and then add 720 lbs. 0 water, an e mixture, to dissolve the same, to abou ,I 7 This solution may then be adde of which has -previously been mix with 1 0 lbs. of w The resultmg product is a aper coating mixture which will flow free y under the brushes of a paper coating machine, and make an adhesive coating and will not show brush marks.

Even with an En lish cla which works fairly well with ordinary starch sizing, it is an advantage to use the alkaline Slllcate, as it gives a thinner working mixture, for paper coating, having less tendency for leaving any brush marks than such coating, without the silicate of soda, has.

The sizing mixture consisting of g modifie rc an an a a me silicatg may b aimfi fldr or wet orm to be subsequently ifiixed with the paper-coating clay and water, as above indicated, to form the paper coating mixture.

Having thus described my invention or discovery I claim and desire to secure by Letters Patent:

1. A sizing, for use in paper-coating, consistin of a mixture of one part of an alkaline s1licate and about twenty-five parts of modified starch.

2. A paper-coating sizing consisting of a mixture of one part of silicate of soda with about twenty-five parts of modified starch.

4L 3 Ext 3. The herein-described method of pre- Intestimon whereof I afiix my signature, paring a paper-coating sizing, consisting in in presence 0 two witnesses. mixing about one part of an alkaline sili- ANDREYV A. DURHAM. cate with about twenty-five parts of modi- Witnesses: 5 fied starch and then dissolving the mixture 0, L. CRUDE,-

by means of a liquid and heat. R. C. Wilcox.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

